Adjustable metal prop



April 26, 1949. J. A. CLARK I ADJUSTABLE METAL PROP Filed Feb. 26, 1947 r rrrrrrrrrrrrrrrr A Patented Apr. 26, 1949 ADJUSTABLE METAL PROP John Alfred Clark, London, England, assignor to Acrow (Engineers) Limited, London, England Application February 26, 1947, Serial No. 730,912 In Great Britain October 22, 1946 1 Claim. 1

The invention relates to adjustable metal props of the kind comprising two telescopic members adapted to be approximately adjusted to position by locating the inner member in relation to the outer member by means of a pin passing through slots in the outer member and holes in the inner member, final adjustment being effected by a nut engaging a threaded portion of the outer member and bearing against the projecting ends of said pin.

The object of the present invention is to prove upon existing constructions, and the invention consists in adjustable metal props of the kind referred to in which the thread upon the outer member is at all times covered or enclosed so that it will not become clogged with dirt or debris and no part of the workmens clothing can be caught up in the threads.

Further features of the invention will be apparent from the description given hereafter.

The accompanying drawings illustrate one convenient form of prop in accordance with the invention.

Figure l is a front elevation.

Figure 2 is a side elevation.

Figure 3 is an enlarged sectional elevation of a part of the prop shown in Figures 1 and 2, and

Figure 4 is a view of a detail.

In carrying my invention into effect in one convenient manner I form my improved adjustable metal prop with two telescopic tubular pieces, the outer one a of which is provided with a suitable foot a and is threaded externally as at a for a part of its length for engagement by a suitable nut b having a handle c or other means for rotating the same. The inner member (1 which slides telescopically within the outer member may be arranged to take varying shapes of head according to the purpose for which the prop is required, and the said inner member is provided with holes d passing diametrically through the said member at spaced intervals throu o its length so that the member may be approximately adjusted. in position by means of a pin e passing through the appropriate one of said holes 11 and through slots a arranged diametrically through the threaded portion of the outer member. Final adjustment is effected by rotating the aforesaid nut 17 which bears against the projecting ends of said pin e.

The nut is formed, or has secured thereto, an imperfcrate sleeve member ,1 of such a length that for all positions of the nut it will efiectively conceal and protect the threaded portion of the outer member located below the nut. The aforesaid pin 6 is carried upon a sleeve member 9 by means of a chain or by appropriate linkage h secured to the said sleeve member and the latter is of such a length that it will at all times effectively conceal and protect the threaded portion of the outer member located above the nut. This latter sleeve 9 has two open-ended slots 5/ (Figure 4) or two holes disposed diametrically at the lower end of the sleeve so as to enable the aforesaid pin 6 to be passed through both telescopic members. The lower sleeve 1 rotates wit the nut, and the upper sleeve 9 rides thereon, and the threaded portion a of the outer member is therefore completely covered throughout the operation of adjusting the .prop with the consequent advantages hereinbefore referred to.

It will be understood that the invention extends broadly to an adjustable prop of the kind to which the invention. relates in which the threaded portion of the outer member is at all times completely covered and protected, and the invention is therefore not to be limited to the particular constructional arrangements hereinbefore given by way of example to indicate the nature of the invention and not to limit its scope.

I claim:

In an adjustable metal prop, the combination of a tubular base having a threaded exterior portion and a pair of longitudinal diametrically opposed slots in said portion; a tubular head coaxial with and vertically slidable in said base and having a plurality of pairs of holes, the holes of each pair registering selectively with said slots, respectively; a nut threaded on said portion for vertical adjustment relative to said base; a bolt removably disposed through said slots and a selected pair of said holes and bearing upon the upper surface of said nut; a tubular sleeve depending from said nut and enclosing a sufiicient length of said base as to cover said portion below said nut when said nut is in any of its adjusted positions; and a second tubular sleeve hearing on said nut and enclosing a sufficient length of said base as to cover said portion above said nut when said nut is in any of its adjusted positions, said second sleeve having a pair of diametrically opposed holes for insertion of said bolt therethrough.

JOHN ALFRED CLARK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,352,117 Pasternack June 20, 1944 FOREIGN PATENTS Number Country Date 69,646 Austria Feb. 15, 1915 162,231 Switzerland Sept. 1, 1933 172,279 Switzerland Dec. 1'7, 1934 

